Balancing Excellent Performance and High Thermal Stability in a Dinitropyrazole Fused 1,2,3,4-Tetrazine

The key to successfully designing high-performance and insensitive energetic compounds for practical applications is through adjusting the molecular organization including both fuel and oxidizer. Now a superior hydrogen-free 5/6/5 fused ring energetic material, 1,2,9,10-tetranitrodipyrazolo­[1,5-d:5′,1′-f]­[1,2,3,4]­tetrazine (<b>6</b>) obtained from 4,4′,5,5′-tetranitro-2<i>H</i>,2′<i>H</i>-3,3′-bipyrazole (<b>4</b>) by N-amination and N-azo coupling reactions is described. The structures of <b>5</b> and <b>6</b> were confirmed by single crystal X-ray diffraction measurements. Compound <b>6</b> has a remarkable room temperature experimental density of 1.955 g cm^–3 and shows excellent detonation performance. In addition, it has a high decomposition temperature of 233 °C. These fascinating properties, which are comparable to those of CL-20, make it very attractive in high performance applications

Silver-Catalyzed Synthesis of 2‑Cyano-5-pyrazolyl‑2<i>H</i>‑tetrazole: A Promising Precursor to Insensitive Energetic Compounds

Exploring new synthetic strategies for designing energetic molecules is one of the key factors in promoting the development of energetic materials. In this study, we report a simple and efficient method for constructing a novel energetic skeleton (2) via silver catalysis. A series of pyrazole-tetrazole energetic derivatives were successfully synthesized using 2-cyano-5-pyrazolyl-2H-tetrazole (2) as a base skeleton. These energetic compounds were fully characterized by nuclear magnetic resonance (NMR) spectroscopy, IR spectroscopy, and elemental analysis. The structures of compounds 5, 6, 8, and 9 were determined by single-crystal X-ray diffraction. The physicochemical properties and detonation performances of all newly synthesized energetic compounds were studied. All new compounds show better detonation performances and lower sensitivities compared with TNT. The detonation performances of compound 10 are close to those of RDX

New Energetic Derivatives of 1-Amino-3-Nitroguanidine

<div><p>Two new energetic derivatives of 1-amino-3-nitroguanidine were synthesized. The furoxan moiety and 2,4,6-trinitrophenyl moiety were introduced to the nitroguanidine frame. The resulting compounds 3-methyl-4-((2-(N′-nitrocarbamimidoyl)hydrazono)methyl)-1,2,5-oxadiazole-2-oxide (<b>1</b>, C₅H₇N₇O₄) and N′-nitro-2-(2,4,6-trinitrobenzylidene)hydrazinecarboximidamide (<b>2</b>, C₈H₆N₈O₈) were characterized by infrared (IR) spectroscopy, multinuclear nuclear magnetic resonance (NMR) spectroscopy, differential scanning calorimetry (DSC), thermogravimetry (TG), as well as elemental analysis. The structure of <b>1</b> was confirmed by X-ray diffraction. Both compounds possess good thermal stability with the decomposition onset temperature above 180°C. Their sensitivity and explosive properties were investigated by experimental and theoretical methods.</p></div

Taming of 3,4-Di(nitramino)furazan

Highly energetic 3,4-di­(nitramino)­furazan (<b>1</b>, DNAF) was synthesized and confirmed structurally by using single-crystal X-ray diffraction. Its highly sensitive nature can be attributed to the shortage of hydrogen-bonding interactions and an interactive nitro chain in the crystal structure. In order to stabilize this structure, a series of corresponding nitrogen-rich salts (<b>3</b>–<b>10</b>) has been prepared and fully characterized. Among these energetic materials, dihydrazinium 3,4-dinitraminofurazanate (<b>5</b>) exhibits a very promising detonation performance (<i>νD</i> = 9849 m s^–1; <i>P</i> = 40.9 GPa) and is one of the most powerful explosives to date. To ensure the practical applications of <b>5</b>, rather than preparing the salts of <b>1</b> through acid-base reactions, an alternative route through the nitration of <i>N</i>-ethoxycarbonyl-protected 3,4-diaminofurazan and aqueous alkaline workup was developed

Practical and Scalable Synthesis of 5,6-Dichlorofurazano[3,4‑<i>b</i>]pyrazine

4H,8H-Difurazano[3,4-b:3′,4′-e]pyrazine (DFP) is an important heat-resistant explosive intermediate, but its current synthesis process is still not scalable due to the low yields and acidic smokes in an internal chlorination step to give the intermediate DHFP. In this work, a DMA-promoted chlorination method to synthesize 5,6-dichlorofurazano[3,4-b]pyrazine is described to solve the bottleneck of DFP synthesis. The best reaction conditions were confirmed to be DMA, DHFP, and POCl3 (2:1:40) at 120 °C for 3 h, with an increased yield of 62%. This new method not only increases the yield but also eliminates the acid smokes during postprocessing, and it is likely to find practical applications in the synthesis of DFP and other heat-resistant explosives